Question

Will the price level always rise when AD increases? LII

Answer 1

This is the fundamental principle of supply and demand, and it is at the core of any market economy. Essentially, you need to look at the supply as the sum of a given product available. Demand refers to the total number of individuals who want the service. The higher the demand, the harder it is to meet the demand for the supply. Producers can create only a certain amount of any product in a given amount of time and sometimes with a limited set of resources needed to create that product.As a result, quantities (supplies) are small, making them more expensive, making people more willing to pay more. Even people who can not afford to pay are sometimes willing to pay the price if the demand is sufficiently high. Conversely, you end up with a surplus when the supply balances the demand. Suppliers have created a product that is not fast enough for consumers to buy. Processes will be discontinued in this case to encourage people to buy the product and reduce supply

This is because of the same explanation that increased demand in microeconomics leads to higher prices.
The idea is that there is more demand, which means more people are willing to buy a particular product. When that happens, people are typically willing to pay higher prices because they know that if they don't pay that price, someone else is going to go and the product is going to go away.
So when there's more demand, there's more "goods chasing money" and prices have to rise and you're going to end up with demand-pull inflation.